Pallets are customarily used to transport and store goods. A pallet typically includes a top deck and a bottom deck separated by support blocks. Pallets have traditionally been formed of wood. While advantageous in terms of cost, wood pallets have many disadvantages. For example, they are subject to breakage and are therefore reusable only over a short period of time. Wooden pallets are also difficult to maintain in a sanitary condition, thereby limiting their usability in applications where sanitation is important, such as in food handling applications.
With growth of the plastics industry a wide variety of plastics have been investigated to determine their suitability for use in producing pallets. Plastic pallets can easily be molded and are stronger and lighter weight than wooden pallets. They can also be made with recyclable materials.
Plastic pallets are generally more durable than wooden pallets. Nonetheless, the support blocks separating the top and bottom decks are subjected to the most intense wear of any part on the pallet since they come into repeated contact with the sharp metal tines of a forklift or pallet jack.
In addition, if the tines of the pallet jack are inserted too far between the top and bottom decks such that the wheels of the pallet jack are resting on the bottom deck, then the top deck becomes separated from the bottom deck when the tines are lifted. The resulting damage from the top deck being separated from the bottom deck requires the top deck to be replaced, and if the damage is too extensive, then the entire pallet is replaced.
If only the support blocks are damaged by the pallet jack, then they may be replaced at a cost far less than replacing the entire pallet. For example, U.S. Pat. No. 5,413,052 discloses a plastic pallet having a top deck and a bottom deck, with replaceable support blocks therebetween. The support blocks include octagonal posts having support member walls positioned beneath reinforced portions of the top deck. The posts also have a sleeve with a central bolt hole parallel to the support member walls. The bottom deck receives the support blocks in recessed pockets. Plastic bolts are inserted through the top deck, each post, and the bottom deck. Plastic T-nuts are used for holding the bolts in place.
In U.S. Pat. No. 4,843,976 a plastic pallet includes identical top and bottom decks interconnected by support blocks. Each support block includes a central core and a surrounding sleeve interconnected by spokes. The core has flexible tabs that extend beyond opposite ends of the sleeve and lock onto the top and bottom decks.
The plastic pallet disclosed in U.S. Pat. No. 5,791,261 also discloses the use of flexible tabs for holding the top and bottom decks together. In particular, the plastic pallet includes support blocks between the top and bottom decks, and upper and lower snap-lock elements extend from the respective top and bottom decks through the support blocks for inter-locking with one another.
While plastic pallets offer several advantages over wood pallets, there is still a demand to increase durability and strength of plastic pallets.